Telephone system



Nov. 22, 1938. F. LILL TELEPHONE SYSTEM Filed Dec. 2. 1935 INVENTOR.FRIEDRICH LILL Tim P i A TTORNE Y. I

Patented Nov. 22, 1938 PATENT OFFICE TELEPHONE SYSTEM Friedrich Lill,Vienna, Austria, assignor to Siemens & Halske Aktiengesellschaft,Wernerwerk, Siemensstadt, near Berlin, Germany Application December 2,1935, Serial No. 52,452 In Austria December 3,1934

, Claims. (01. 179-30) In telephone systems in which alternatingcurrent'impulses are transmitted over the connectingline care has to betaken that the transmiss-ion of alternating. current, which passes overthe 5 line in both directions during the call and brings about switchingoperations atboth ends of the connecting line, takesiplacesystematically so'that the alternating current impulses do not proceedsimultaneously thereby preventing important switching operations fromtaking place.

This systematic operation cannot be observed, however, when-telephonesystems having subscribers provided with magneto ringing are involved inwhich unforeseen alternating currents may be transmitted at all stagesof the call.

,The invention resides in that, in systems in which alternating currentimpulses are sent out from, anexchange and which have subscribersstations provided with magneto operation, the transmission of individualalternating current impulses seizing and releasing impulses) efiected bythe exchange, which are ofimportance for the call and which controlconnecting devices, is delayedin the event of the subscribertransmitting 25 alternating current either simultaneously with or partlybefore the impulse transmission, during the time thus occupiedby themagneto current.

A further characteristic of the invention resides in that in theexchange devices, only alternating current impulses sent out by theexchanges in.- volved are operative, dependent on their duration andsequence, and that the duration and sequence of the alternating currentimpulses passing over the connecting line are supervised in theconnecting devices by means of relay combinations.

The drawing represents an embodiment of the invention. A system is shownfor communicating from subscribers connected to a party line who areprovided with local battery and magneto stations in which all callsincluding internal calls are set up in a semi-automatic manner by waydesires. a connection ;with another subscriber of the same localexchange or group. Since the establishment of all calls is onlysemi-automatic he must call up 'the communicating or main ex- 55' changeover the connecting trunk line.

It will be assumed that one of the subscribers The call is set up by-thetransmission of alternating current from the magneto of the callingsubscriber whereupon the speaking leads of the subscriber are switchedthrough on to the leads a and b in the ,relayrepeating device which isnot shown since it is not essential ,forunderstanding the invention Thealternating current sent out by the subscriber energizes the alternatingcurrent relay W3 whichswitches the line through at contacts 31w3whereuponthe drop FK associated with the cut-ofi jack Klz is alsooperated over the connecting line'VLtgwhich terminates in repeatingcoils UI and U2. The operatorof the connecting exchange is therebyinformed of the existence of the call and inquires by plugging into thejack. t

' The drop FK isidisconnected by the plug and the jack contacts l3klioperated. The following switching operations take place: Relay Denergizes over earth, l3klz', Hwl, Illal, Wil, D, and battery, whereuponrelay E energizes over earth, 38d and Wi2, and the relay F over earth,32c, W14, F, and Wi3. The adjustment of relays D, E, and F overresistances Wil, WiZ, and Wz'4 is such that these relays, which aremoreoverprovided with a copper sleeve over the core, energize relativelyslowly. From the operation of the'jack contacts l3klz' until theenergizing of relay F, relay RI remains energized. It energizes in thecircuit: earth, l3kli, Hwl, lflal, 8d, 1112,61, RI, and bat tery, andlocks up, after the opening of contact 8d, at contact am until it is,disconneced by contact 61. Over contacts 211'! and 2811 an alternatingcurrent seizingimpulse is applied to the connecting line throughout thetime during which relays D,E, and F are energized. By means of thisimpulse relay W2 is energized over the line. Contact 541,0 2 of relay W2causes relay G to energize over contact 53k. This relay energizes relayH by means of contact 51g and the latter relay brings up relay K overcontact-56h. Contact 5370 disconnects relay G again and locks up relay Kuntil contact 54102 opens. Contact 38k disconnects the speaking line.Relays G and subsequently H make a delayed release. When the seizingimpulse comes to an end relay H still re-' mains energized after relayW2 releases since the seizing impulse only lasts during the energizingperiod of three relays (D, E and F), so that now relay B energizes overearth, 44102, 4519(2), 46h, Wz'5; B, and battery. Relay B is constructedas a two-stage relayand on being operated over Wi5 only operates contact4'lb(l). The contacts operated when the relay is fully energized bearthe index (2) "7, After the release of relay Hrelay B establishes alocking circuit, earth, 48rt, 4'Ib( I) in which it energizes fully onaccount of Wi5 having been short circuited at 46h. The speaking line isswitched through by means of contact 3617(2). Contact 42b(2) seizes therelay repeater device over the c-lead in a corresponding manner.

If the subscriber transmits alternating current by operating his magnetowhile the plug is inserted in the jack, the transmission of the seizingimpulse does not take place until relay WI deenergizes again, since thisrelay energizes and opens contact IIwI. Relays D, etc. then energizeover contacts I3kli, IIwI, etc. whereupon relay RI is energizedtransitorily, etc. as has already been described.

After the enquiry on the part of the operator the latter dials impulsesover the line, since the subscriber desires a connection with thesubscriber of the same-group. It is assumed that the impulsestransmitted over the line do not operate directly upon the connectingdevice of the subscriber on account of their relatively high frequency,but are registered in the relay repeating device and are given out againmore slowly.

The registering device in the relay repeater is connected up by theoperation of the a key on the part of the operator, closing contactsIBET and ET. Relay AI is energized in the circuit earth, ISET, AI, A21and battery. Relay A2 receives insuiilcient current through its windingA21, and does not energize. Relay RI energizes again over earth,IaI, M2and 8! until relay F, which is short circuited by 35ET, deenergizes.After the release 01 the key comprising contacts I SET and 35ET relay AIlocks up over earth, I3kli, I5al, A211, AI, A21 and battery, and relayA2 now energizes since both its windings are subjected to current. RelayF likewise energizes slowly over the resistance WM and the otheroperations take place as described earlier so that meanwhile relay A2becomes energized.

When now relay RI is switched over again it can no longer energize sincecontacts IaI and 2112 are operated. Contacts 2111 and 28H connectalternating current transitorily to the line so that relay W2 energizesand brings up relay G by means of contact 54w2. Relay H energizes over51g and relay K over 56h. Relay R2 does not energize in response to thisbrief impulse over earth inthe relay repeater, lead e, 5Ib(2), 50k: and49102 since it is provided with means (a copper slug fitted to the core)making it slow to energize. The earth connected over 601122 and lead 1is likewise inoperative before the registering device in the relayrepeater has been connected up. The registering device is connected upafter the release of relay W2, over earth, 44w2, 4517(2), 43h and theline d. Contact 43h is still operated since the relays release slowlyone after the other,'after relay G has been disconnected. The operatorcan be informed over the speaking line that the connection has takenplace, by means of an audible signal, so that the depressing of the keycomprising contacts ISET and 35ET can be repeated if for any reason theconnection does not take place, for example on account of asimultanecus'transmission of alternating current on the part of thesubscriber. On the connecting up of the registering device the speakingline is out off in the relay repeater so that the transmission ofalternating current on the part of the subscriber can no longer be asource of disturbance.

The desired number is now dialled and is taken up by theregistering-device of the relay repeater.

The dial impulse contact 51m energizes relay RI intermittently over 5nsiand earth. Contacts NH and 28rI connect alternating current to the lineand relay W2 is energized intermittently. The impulses are transferredto the registering device over earth, 6Ilw2 and the lead 1. Duringdialling relays G, H, and K hold up throughout the impulse trains. RelayR2 cannot energize while dialling is in progress since the lead e isdisconnected in the relay repeater.

When the registering device has been set the impulses are released bythe operation of a key comprising contacts 2IAT and 34AT. Since relaysAI and A2 are still energized, relay A2 holds up throughout the timeduring which the key is depressed, over earth, 2IAt and 20a2, whilerelay AI is short circuited and releases. Relay RI is accordingly againenergized over IaI, 2a2 and 6 and transmits an impulse over contacts2'IrI and 28. 4. The impulse is limited by contact SI, for relay F isshort circuited over 33aI and 34AT and deenergizes. After the release ofthe key relay A2 deenergizes and relay F becomes energized. The releaseperiod of relay A2 is smaller than the energizing period of relay F sothat relay RI is not again energized. By means of the alternatingcurrent impulse relay W2 is energized transitorily and operates relay Gover 54w2, the latter relay brings up relay H at contact 519 and this inturn energizes relay K over 56h. The alternating current impulse of thesame duration as that causing the registering device to be connected upcannot energize relay R2 which is slow to energize. An additionalsetting in the registering device by way of contact 60102 is thusprevented. On the termination of the impulse earth is again connected tothe d-lead over contacts 43h, 45b(2) and 44202, whereby the impulsetransmission is released in the relay repeater. The operator receives anaudible signal over the line until the impulse emission has terminated.

Subsequently the speaking line is again switched through in the currentrepeater to the subscriber, the latter being called by the transmissionof ringing current over the jack Kli. This transmission of ringingcurrent is more prolonged than the controlling impulses so that relay R2energizes over earth in the relay repeater, lead e; 5i 21(2), k, and49102, and transmits the ringing current over contacts "r2 and 4Ir2 tothe subscribers who are now both called.

The clearing signal is given by one of the two subscribers by means ofthe magneto, whereupon relay W3 energizes and disconnects relay W2 atcontact 31103. In addition to the clearing a drop in the supervisorycord circuit is operated, whereupon the plug is withdrawn and the jackcontact I3kli is switched back to normal. Current passes through relaysAI and A2 over earth, I3kli, "L, and IN. The two relays energizesimultaneously so that contacts In! and 20:2 are switched over withoutrelay RI having been energized. Relay L energizes over earth, I3kli,22wI, MM, and 26d, and disconnects relays AI and A2 at contact I'IL.Relay A2 deenergizes rapidly but relay AI makes a delayed release.Meanwhile relay RI is energized over earth, IaI, 2a2, 6], RI and batteryand connects alternating current to the line at contacts 21M and 2811.After the release of relay A2 the L relay holds up over earth, lakli,22wI, 231, 251 until relay F deenergizes on the completing of therelease. Contact IOaI disconnects relay D, 3011 disconnects relay E and322 relay F. Over contacts 3e, 4d and 6f relay RI, which has in themeantime released, again becomes energized. Meanwhile, a second impulseis transmitted over the line. Thus, for the purpose of release, tworelatively short impulses separated from one another by an intervalcorresponding to the release period of two-relays ar transmitted overthe line. Relay W 2 is energized twice. Contact 39102 disconnects relayW3 and the relay repeater. 611 the first energizing of relay W2 relay Genergizes. Contact iilg energizes relay H, and 5th relay K. Relay Gholds up over 55102 and 5219(2). After the impulse the relays G, H, andK release in succession. When the second impulse occurs relay K has notyet deenergized and relay ET is energized. Contact liirt disconnectsrelay B and the release is effected by 27163). All the subsequentoperations in the relay repeater have no bearing on the invention andwill not further be described.

In the event of the subscriber transmitting alternating current from hismagneto while the plug is being withdrawn, relay W l is energized andprevents the release by means of contact 22ml. Meanwhile contact ltwlholds relay Al energized over contact Mal and the latter relay holds uprelay D over lilal. After relay Wl deenergizes the release proceeds asalready described.

What is claimed is:

1. In a telephone system, a local exchange having magneto lines, a mainexchange connected to said local exchange by a trunk line, meansresponsive to a call from a magneto line for signailing the operator atsaid main exchange by transmitting alternating current over said trunkline, means controlled by the main exchange operator for transmittingalternating current back over said trunk line to said local exchange toestablish a connection with the calling ma neto subscriber, and meansautomatically opermm for delaying the transmission of the alter natingcurrent by the operator controlled means in the event that the callingmagneto subscriber transmits further alternating current at the time theconnection is being established by the operator.

2. In a telephone system, a local exchange having magneto lines therein,a main exchange connected to said local exchange over a trunk line,means responsive to a call from a magneto line for transmittingalternating current over said trunk line to signal the main exchangeoperator, means controlled by the main exchange operator fortransmitting an alternating current impulse back over said trunkline tosaid local exchange to establish a talking connection with the callingline, and means in said main exchange for automatically delaying'thetransmission of the alternating current impulse to the localexchange 4. In a telephone system, a local exchange having magnetolines, amain exchange connected to said local exchange by a trunk line,means responsive to a call from a magneto line for signalling theoperator at said main exchange by transmitting alternating current oversaid trunk line, means controlled by the main exchange operator fortransmitting alternating current seizing, connecting, and releasingimpulses of only a particular duration and sequence back over said trunkline to said local exchange, switching equipment at said local exchangeresponsive to said alternating current impulses for establishing aconnection with a desired magneto subscriber, and means for delaying thetransmission of the alternating current impulses by the operatorcontrolled means in the event that the calling magneto subscribertransmits further alternating current which is of a different durationand sequence at the same time or partly before said impulses aretransmitted by the operator controlled means to establish a connection.

5. In a telephone system, a local exchange having magneto lines therein,a main exchange connected to said local exchange over a trunk line,means responsive to a call from a magneto line fortransmittingalternating current over said trunk line to signal the mainexchange operator, a relay chain combination in said main exchangecontrolled by operator for transmitting alternating current seizing,connecting, and releasing impulses of a definite duration and sequenceback over said trunk line to said local exchange, switching equipment atsaid local exchange responsive to said alternating current impulses forestablishing a connection with a wanted local exchange magneto line, andmeans in said main exchange for temporarily delaying the transmission ofsaid alternating current impulses by said relay chain combination in theevent that the calling magneto line transmits additional alterhatingcurrent of difierent duration and sequence at the same time said otherimpulses are being transmitted to said local exchange.

FRIEDRICH LILL.

